What is a tact in ABA?
A tact is the verbal operant of labeling - communication occasioned by seeing, hearing, or otherwise sensing something and maintained by social acknowledgment rather than by receiving the item itself.
When a child points at a dog and says 'dog', nothing tangible changes hands - the reinforcement is the parent's 'That's right, a dog!' That is the signature of the tact: it is controlled by the thing noticed, not by wanting it, and it is maintained by social consequences.
The distinction from the mand is easy to see with one word in two moments. 'Water' said while reaching toward the tap, satisfied only by a drink, is a mand. 'Water' said while pointing at a lake, satisfied by agreement, is a tact. Same word, different operants - and a learner can have one without the other, which is exactly why programs assess and teach them separately.
Tacts are the backbone of vocabulary growth because they connect language to the world. Programs typically expand tacting from objects to actions, features, categories, and eventually private-ish events like emotions on faces - each expansion widening what the learner can comment on and setting up later conversational skill.
Because the natural reinforcement for tacting is social, the skill depends on attention and shared engagement being reinforcing in the first place. Early programs often spend deliberate effort making social acknowledgment matter - which is part of why pairing and rapport-building precede formal targets.
A practical marker of a maturing tact repertoire is spontaneity: labels offered unprompted, about new things, to new people. Session data that separates prompted from spontaneous tacts shows whether the skill is genuinely the learner's or still the therapist's.